This proposal is to investigate the influence and interaction of familial, nutritional, behavioral, and neurophysiological factors on the blood pressures of normotensive blacks. The most significant singular objective is to implement a definitive investigation of cardiovascular response to dietary manipulations of sodium and calcium in young blacks who may be at risk of developing premature essential hypertension. An investigation is proposed which enables analyses of interacting nutritional, familial, and behavioral factors influencing cardiovascular reactivity to mental, physical, and dietary challenges. These objectives will be accomplished with a cross-over design by the implementation of a twelve-day dietary protocol which is preceded by psychological testing, and concluded with well-established methods of reactivity testing. Important information will be obtained concerning characteristics of individuals vulnerable to hypertension as well as the utility of nutritional and behavorial interventions for the prevention of premature cardiovascular disease in blacks.